Quote from AmberGreen
On August 21st, all game servers, SWTOR.com, and the launcher will be unavailable as we perform scheduled maintenance.
Game Update 2.3.1 will be implemented during this downtime. Details are as follows:
Date: Wednesday, August 21st, 2013
Duration: 4 hours
Time: 3AM PDT (10AM UTC) - 7AM PDT (2PM UTC)
During maintenance, all updates and additional information will be posted on our Twitter account.
Thank you for your patience as we maintain service for Star Wars™: The Old Republic™.